Pollution of the environment and particularly of the atmosphere is a permanent preoccupation in the center of controversial disputes. An important part of the air pollution caused by industries can be coped with by a measure of additional investment for the preliminary treatment of the fuel or by the treatment of the noxious products of combustion by electrofilters, catalzers, gas washing and similar equipment built into existing fireplaces. The pollution caused by big, usually dual-fuel, slow speed industrial ICE lies in a more or less acceptable range. The evil increases with the increase of the speed of the engine which improves its efficiency but shortens the time of combustion, causing a low volumetric efficiency and an incomplete scavenging of burned gases resulting in an incomplete combustion and noxious exhaust.
These imperfections, largely responsible for the degradation of the environment, are a consequence of the more than 100-year-old constructional conception of the conventional ICE. Disregarding the tremendous improvement of its mechanical properties and technical performances realized during that period of time, it still represents a simple, technologically poor engine, with an extremely low thermal efficiency.
Its construction features as well as its method of operation are equally responsible for its low output and the nauseous exhaust. Whatever the proportion of the air fuel mixture taken into the cylinder or obtained by the fuel injection in the compressed air of an ICE, clean exhaust can never be achieved due to the lack of time needed for a complete combustion, limited by the duration of a single variable-volume power stroke.
The combustion time is further shortened by the high speed of the engine, necessary to improve its efficiency, which in turn requires the use of rapidly-burning high-quality fuels. Nevertheless, the largest part of the calorific value of these expensive fuels is dissipated due to the fact that the combustion occurs practically in an "open valve" condition, caused by the short time available for the scavenging of the burnt gases and the intake of fresh air.
It should also be mentioned that the conventional ICE lacks space for the installation of the valves in a number and size necessary for an improved air intake and exhaust off the burned gases. Also it is difficult to realize a gas-tight separation of the working cylinder from the crankcase in order to prevent a rapid degradation of the lubricating oil and avoid the ventilation of the crankcase through the carbureting system of the emgine. Another all-important disadvantage is the tremendous loss of heat caused by the cooling system of the ICE.
A turbocharger improves the mechanical efficiency of the ICE by allowing the injection of a larger quantity of fuel into a larger quantity of compressed air without improving the combustion or changing anything in the method of operation of the engine. On the other hand the catalyzer is an auxiliary palliative device which can reduce to a certain extent the toxicity of the exhaust gases on condition that their quantity, depending on the speed of the engine, is proportional to the filtering surface of the catalyzer. Nevertheless, it cannot solve the problem of pollution. Both devices seriously increase the price of the engine and require permanent servicing and maintenance.
Furthermore the different types of conventional ICE are of a different constructions substantially differing from each other with respect to the working cycle, kind of fuel and method of operation. The configuration of a two-stroke conventional diesel engine is entirely different from the basic structure of a four-stroke diesel engine. The difference is even greater in case of its hybrid and special purpose variant, which has very little in common with the basic four-stroke structure of the ICE (ACRO, LANOVA, BUECHI, PESCARA etc.--Prof. Fritz A. F. Schmidt "Verbrennungs-kraft-maschinen" Springer Verlag 1967, pages 181/183, 230/232, 296/297, 417). Moreover, none of these constructions solves the above enumerated problems.